I was playing more Halo 3 on my 360 last night and I was getting frustrated by the auto aim. Yes, dual analog was not designed to aim quickly or efficiently, but I'm at terms with that and I don't mind. I don't see why it needs to be compensated for so much. Most of the enemies in Halo 3 already move like they're in slow motion, giving players plenty of time to aim (this is in stark contrast with, for example, Metroid Prime 3 where you have to aim very precisely and very quickly while dodging attacks).
The auto aim is egregious. I employ the "flick" method to aim and somehow I was 'tracking' slow-moving enemies through the air. I don't want the game to aim for me. The enemies barely move as it is.
For those of you who have played Metroid Prime 3 and Halo 3, do you find the contrast stark? In MP3 the enemies and bosses moved so quickly and required such accurate aiming that I'm more used to fast-paced precision than enemies moving in slow motion and the game aiming for you. The ice boss in Metroid Prime 3 is a perfect example of how fast bosses can be, and the boss with the "eyes" that you have to shoot is a perfect example of the precision required.
I realize that the Wii mote has a natural advantage over the 360's controller for shooters, but I still think the constast between the two games is amazing.